Capacitive Reactance
Capacitive reactance is the opposition a capacitor presents to alternating current (AC). Unlike resistance, it varies with frequency reactance decreases as frequency increases. This is fundamental to designing low-pass/high-pass filters, coupling/decoupling networks, and impedance matching circuits.
Capacitive reactance
XC1.592 kΩ
FormulaXC = 1 ÷ (2π × f × C)
PhaseCurrent leads voltage by 90°
Formulas used
XC = 1 ÷ (2π × f × C)
How to use this calculator
Step-by-Step Instructions
- Enter the AC frequency in Hz (e.g., 50Hz for mains, 1000Hz for audio, 1000000 for 1MHz RF).
- Enter the capacitance in µF. Convert nF to µF by dividing by 1000, or pF to µF by dividing by 1000000.
- Click Calculate The reactance is displayed in Ohms.
Worked Example
10µF capacitor at 1kHz: Xc = 1 ÷ (2π × 1000 × 0.00001) = 15.92Ω